1. Field of the Invention
This invention relates to high speed photodetectors, and, more particularly, to high speed photodetectors incorporating an interdigital metal electrode pattern formed on a heterostructure configuration. By high speed is meant that the analog frequency response is greater than about 1 GHz, or, the device rise and fall times are less than about 200 ps.
2. Description of the Prior Art
Conventional photoconductive detectors rely on the difference in the transit time of one carrier type versus the recombination time of the other carrier type to achieve gain. This is at the cost of device speed. The use of photoconductive two-terminal devices for high speed photodetection has been proposed by Sugeta et al, Vol. ED-26, IEEE Transactions on Electron Devices, pp. 1855-1859 (1979) and Gammel et al, IEDM Technical Digest, pp. 634-637 (1979). However, both types of devices rely on blocking contacts and are recombination-time limited.